1. Field of the Invention
The present invention relates to a flexible printed circuit board, and more particularly to a flexible printed circuit board having an improved reinforcing structure.
2. Description of the Related Art
In today's information society, various electronic products are increasingly used in daily activities. To meet the market demands for high-speed, high-efficiency and small-sized electronic products, flexible printed circuit (FPC) boards have been used in various electronic devices, such as notebooks, cell phones, digital cameras, personal digital assistants (PDAs), printers, and optical disk drives. In these various electronic devices, the FPC boards are mainly used as means for connecting two electronic circuits distant from each other, wherein one of the electronic circuits includes an electrical connector for electrically connecting with the FPC board. In some applications, in order to be more space efficient, the FPC boards are even bonded with IC chips thereon.
Please refer to FIG. 1A, an assembly of a conventional FPC board 100, an electrical connector 10 and a printed circuit board (PCB) 20 is shown. FIG. 1B is a schematic bottom view of the FPC board 100 of FIG. 1A.
Referring to FIGS. 1A and 1B, the conventional FPC board 100 is inserted into the electrical connector 10. The electrical connector 10 is electrically connected to the printed circuit board 20; thus, signals can be transmitted between the conventional FPC board 100 and the printed circuit board 20 via an electric terminal portion 112 of the conventional FPC board 100 and the electrical connector 10.
The FPC board 100 includes a flexible substrate 110 and the electric terminal portion 112 disposed on a bottom surface 110b of a front end of the flexible substrate 110. Since the flexible substrate 100 is made of flexible material, a reinforcing structure 120 is required to be applied to the flexible substrate 100 at a position corresponding to the electric terminal portion 112 whereby the electrical terminal portion 112 can be correctly inserted into the electrical connector 10 to electrically connect therewith. Here, the reinforcing structure 120 is disposed on a top surface 110a of the front end of the flexible substrate 110. When the front end of the flexible substrate 110 is inserted into the electrical connector 10, the electric terminal portion 112 (shown in FIG. 1B) disposed on the bottom surface 110b of the flexible substrate 110 electrically engages with a electric terminal portion (not shown) of the electrical connector 10 which is soldered to the printed circuit board 20.
It is noticed that a thickness T of the reinforcing structure 120 is often limited under structural consideration, which in turn results that the reinforcing structure 120 can not have a thickness large enough to provide sufficient rigidity required for the front end of the FPC board 100. A sufficient rigidity is required to ensure that the front end of the FPC board 100 can be smoothly inserted into the electrical connector 10 without occurrence of warpage. Furthermore, for a small thickness T, a rear edge of the reinforcing structure 120 has a small surface area, which is a place for a user's fingers to exert a force to push the front end of the FPC board 100 into the electrical connector 10. For a small surface area of the rear edge of the reinforcing structure 120, the user is not convenient to exert the pushing force. Finally, there is no place on the FPC board 100 which can facilitate the user to conveniently pull the FPC board 100 away from the electrical connector 10 when the front end of the FPC board 100 is required to be separated from the electrical connector 10